Interpretive Summary: Neuropathic pain is defined as a type of pain caused by the dysfunction of the nervous system. In the world, as much as 7% - 8% of the population is affected, and in the United States, more than two million people suffer neuropathic pain. Treatment of neuropathic pain is currently difficult and challenging. Opioid and cannabinoid receptor agonists are potent analgesics and remain the more effective treatments for patients with neuropathic pain. This research reports such compounds of potential utility in researching therapies for neuropathic path. The compounds are products of a fungus, Eurotium repens.

Technical Abstract:
Bioassay-guided fractionation of the fungus Eurotium repens resulted in the isolation of two benzyl derivatives, repenol A (1) and repenol B (2). Seven known secondary metabolites were also isolated including five benzaldehyde compounds, flavoglaucin (3), tetrahydroauroglaucin (4), dihydroauroglaucin (5), auroglaucin (6) and 2-(2’,3-epoxy-1’,3’- heptadienyl)- 6-hydroxy-5-(3-methyl-2-butenyl)benzaldehyde (7), one diketopiperazine alkaloid echinulin (8) and 5,7-dihydroxy-4-methylphthalide (9). The structures of these compounds were established on the basis of extensive 1D and 2D NMR spectroscopic analysis and mass spectrometric (ESI-MS) data. Compound 1, 2, 3, 4 and 6 show good binding affinity for human opioid receptor or cannabinoid receptors. These findings have important implications for psychoactive studies with this class of compounds.